The present invention relates to a system for recognizing bar codes having wide and narrow bars, and more particularly to a system in which a threshold value for discriminating each bar width is corrected automatically.
A bar code recognition system in which an information is coded into a bar code and each information is recognized by scanning each bar code is known well. It is also a well known matter in this prior art system that the bar code is scanned and converted into a rectangular signal having a time width proportional to each bar width, and the bar width is discriminated by comparing each time width of the rectangular signal with a threshold value, thus decoding the bar code. The threshold value is predetermined to be constant in general, therefore the validity of decoded information becomes low when, for instance, some of bar codes are recorded smaller than the other.